#include <stdio.h>

int main(void)
{
    int a,b,ans;
    scanf("%d%d",&a,&b);

    if(a+1 < b){
        printf("YES\n0\n");
    } else {
        ans = a-b+1;
        printf("NO\n%d\n",ans);
    }
    return 0;
}